Vitamin B12

Other names: cobalamin, hydroxocobalamin, Cobalin-H

Vitamin B12 is a water-soluble vitamin that plays an important role in the production of your red blood cells. It also helps in maintaining the normal functioning of your brain and nervous system. It’s found in several foods including meat, fish, eggs, dairy products and some fortified breakfast cereals. 

You need vitamin B12 to help maintain your nerves’ myelin sheath. If you are deficient in vitamin B12 you can get symptoms that are similar to some of the symptoms of MS, such as fatigue, weakness, numbness or tingling and problems with memory. For this reason, if your doctor suspects that you may have MS, part of the NICE diagnosis guidelines includes a blood test to rule out vitamin B12 deficiency as a cause of your symptoms. 

Some studies have found a higher rate of vitamin B12 deficiency in people with MS than in people without MS. One study found that although the levels of B12 in the blood were normal in people with MS, the levels in their cerebrospinal fluid were lower than usual, although the reason for this difference was not clear. Other studies have found no link between vitamin B12 deficiency and MS.

If you are a person with MS and your vitamin B12 levels are within the normal range, there’s no research evidence suggesting that taking vitamin B12 supplements would benefit you. If you follow a vegan diet, you may need to take care to ensure that you are getting enough B12, as the only vegan sources are fortified cereals or dietary supplements.

Despite the lack of research evidence, some people with MS use monthly injections of vitamin B12 as a treatment for fatigue. The NICE guidelines for MS do not support this, so this treatment would not normally be available on the NHS in the UK. 

Vitamin B12 supplements were one of the elements of the Cari Loder regime.

Find out more

Nijst TW, et al.
Vitamin B12 and folate concentrations in serum and cerebrospinal fluid of neurological patients with special reference to multiple sclerosis and dementia.
Journal of Neurology, Neurosurgery and Psychiatry 1990;53:951-954.
Full article (link is external)
Vrethem M, et al.
Increased plasma homocysteine levels without signs of vitamin B12 deficiency in patients with multiple sclerosis assessed by blood and cerebrospinal fluid homocysteine and methylmalonic acid.
Multiple Sclerosis Journal 2003;9(3):239-245.
Summary (link is external)
Wade DT, et al.
A randomised placebo controlled exploratory study of vitamin B-12, lofepramine, and L-phenylalanine (the "Cari Loder regime") in the treatment of multiple sclerosis.
Journal of Neurology, Neurosurgery and Psychiatry 2002; 73:246-249.
Full article (link is external)